2b:null 2c:["$","title",null,{"children":"Air Quality Measurements in Tower Hamlets | Save our Safer Streets | Observable"}] 31:T633,# Air Quality Measurements in Tower Hamlets ## Air Quality Measurements (NO₂) in Tower Hamlets before and after Low Traffic Neighbourhoods Low traffic neighbourhoods (LTNs) have been in place and operational in Tower Hamlets since July 2021. ### What we did We wanted to see if air quality levels have changed since the new LTN road layouts in Tower Hamlets. ### How we did it We conducted our analysis using data received from a Freedom of Information request and data provided on the Tower Hamlets Council's [website](https://www.towerhamlets.gov.uk/lgnl/environment_and_waste/environmental_health/pollution/air_quality/Advanced_information_on_air_quality/Monitoring.aspx). This is data collected in monthly intervals using Tower Hamlets' Nitrogen Dioxide Diffusion Tubes. Altogether, the available data starts from May 2015 and runs to July 2022. For our analysis, we compared air quality levels before and after the Low Traffic Neighbourhoods (LTNs) were installed in the borough. We used the air quality measurements taken from areas closest to the LTNs, comparing like-for-like 7-month-periods: Jan-Jul 2019 (before) and Jan-Jul 2022 (after). *Disclaimer: This analysis was done by volunteers working with the [Save Our Safer Streets campaign](https://heartbg.uk). Where possible, we've sought advice and comment from third parties with relevant experience or expertise. We ask that Tower Hamlets council undertake professional and verified analysis to understand the impacts of the LTNs and to determine the borough's needs and how best to serve its communities.*32:T5ca,

Key Results

Pollution levels have fallen since the LTNs were installed: There have been falls in pollution for areas within and surrounding Tower Hamlets' LTNs. Comparisons before and after the LTN installations show declines in NO₂.

Pollution levels fall more on Hackney Road and Bethnal Green Road than Tower Hamlets as a whole: On major artery roads near to LTNs (Hackney Road and Bethnal Green Road) falls in NO₂ are greater than the falls across Tower Hamlets as a whole.

Tower Hamlets Pollution levels have fallen since 2015: Since the Nitrogen Dioxide Diffusion Tube programme began in Tower Hamlets (May 2015), the trend has been a fall in the borough's pollution levels.

Average pollution levels are falling below the national target: From 2021, annual average pollution levels in Tower Hamlets have fallen below the ["National Air Quality Objective"]( https://uk-air.defra.gov.uk/assets/documents/Air_Quality_Objectives_Update.pdf) or national target of 40 µg/m3 of Nitrogen Dioxide (in-line with [national trends](https://www.gov.uk/government/statistics/air-quality-statistics/ntrogen-dioxide)).

33:T3a5d,

	2015	2016	2017	2018	2019	2020	2021	2022*
Bethnal Green Rd/ Brick Lane	43.3	59.14	58.26	46.89	48.78	39.96	33.76	36.11
Calvert Ave/Boundary Street	38.8	53.22	51.88	48.88	46.21	38.75	28.15	26.87
Columbia Rd/Gossett Street	35.67	48.68	50.49	45.14	43.65	37.24	27.5	27.23
Grove Rd/Old Ford Rd	43.36	62.05	59.36	55.96	53.98	39.73	34.4	34.86
Paradise Row/Bethnal Green Rd	45.04	57.24	54.17	54.18	48.02	40.91	35.99	35.83
Parmiter St/ Cambridge Heath Road				58.87	54.49	44.13	36.58	36.99
Queensbridge Rd/Hackney Rd				72.96	47.02	38.14	31.29	31.25
Roman Rd/Globe Road				47.65	45.51	37.64	34.39	33.06
Squirries St/Gosset St				50.46	50.07	39.5	32.61	32.51
Warner Place/Hackney Rd	39.64	53.44	52.88	49.92	47.26	37.16	28.9	31.17
Whitechapel High St (KFC)	66.58	82.53	80.93	80.47	63.79	51.15	48.33	51.94

34:T3cd1,

	2015	2016	2017	2018	2019	2020	2021	2022*
Bethnal Green Rd/ Brick Lane	46.98	45.54	44.28	35.64	36.58	27.4	26.33	27.08
Calvert Ave/Boundary Street	42.1	40.98	39.43	37.15	34.66	26	21.96	20.15
Columbia Rd/Gossett Street	38.46	37.48	38.37	34.3	32.74	24.9	21.45	20.42
Grove Rd/Old Ford Rd	47.05	47.78	45.12	42.53	40.49	27.5	26.83	26.15
Paradise Row/Bethnal Green Rd	49.64	44.07	41.17	41.18	36.01	28.1	28.07	26.87
Parmiter St/ Cambridge Heath Road				44.74	40.87	30.3	28.53	27.74
Queensbridge Rd/Hackney Rd				55.45	35.26	26.2	24.41	23.44
Roman Rd/Globe Road				36.21	34.13	25.8	26.82	24.80
Squirries St/Gosset St				38.35	37.55	27.1	25.43	24.38
Warner Place/Hackney Rd	42.01	41.15	40.19	37.94	35.44	25.5	22.54	23.38
Whitechapel High St (KFC)	72.24	63.55	61.51	61.16	47.84	33.9	37.7	38.96

35:T4d7,Plot.plot({ color: { type: "categorical", scheme: "pastel1" }, x: { label: "", domain: ["before", "after"], //tickFormat: (d) => d.split("-")[0] }, y: { label: "↑ Average air quality (NO2 µg/m3) for" + " " + selectLocation_3, grid: true, inset: 3 }, marks: [ Plot.barY(aq_before_after_jan_jul.filter(d => d.aq !== 0 && d.location === selectLocation_3), Plot.groupX( {y: "mean"}, { x: "period", y: "aq", sort: null, fill: "period", fillOpacity: 0.4, //filter: (d) => d.location === selectLocation_3 })), Plot.text(aq_before_after_jan_jul.filter(d => d.aq !== 0 && d.location === selectLocation_3), Plot.groupX( {y: "mean", text:"mean"}, { x: "period", dy: 12 })), Plot.ruleY([0]), //Plot.text(aq_before_after_jan_jul, {x: "period", y: "aq", text: d => d3.mean(d.aq), dy: -5, filter: (d) => d.location === selectLocation_3}) ], marginLeft: 50, // space to the left of the chart marginBottom: 30, // space below the chart insetBottom: 33, // space between the x-axis and the marks insetLeft: 5, marginTop: 20, width: 240 })36:Taeb,Plot.plot({ height: 90, width: 380, axis: null, marginBottom: 10, marginTop: 10, marginRight: 15, y: { domain: [0, 8] }, x: { domain: [0, 9] }, marks: [ Plot.text([[1, 0]], { x: 2, y: 8, text: ["Before"], lineHeight: 1, fontSize: 12 }), Plot.text([[1, 0]], { x: 5, y: 8, text: ["After"], lineHeight: 1, fontSize: 12 }), Plot.text([[1, 0]], { x: 8, y: 8, text: ["Difference"], lineHeight: 1, fontSize: 12, textAnchor: "middle" }), Plot.text(aq_before_after_jan_jul, { x: 2, y: 6, text: d3.mean(aq_before_after_jan_jul.filter(d => d.aq !== 0 && d.location === selectLocation_3 && d.period === "before"), d => d.aq), filter: d => d.location === selectLocation_3 && d.period === "before", lineHeight: 1, fontSize: 12, monospace: true, fontWeight: "normal" }), Plot.text(aq_before_after_jan_jul, { x: 5, y: 6, text: d3.mean(aq_before_after_jan_jul.filter(d => d.aq !== 0 && d.location === selectLocation_3 && d.period === "after"), d => d.aq), filter: d => d.location === selectLocation_3 && d.period === "after", lineHeight: 1, fontSize: 12, monospace: true, fontWeight: "normal" }), Plot.text(aq_before_after_jan_jul, { x: 7, y: 6, text: ["↓"], lineHeight: 1, fontSize: 12, textAnchor: "start" }), Plot.text(aq_before_after_jan_jul, { x: 8, y: 6, text: d3.mean(aq_before_after_jan_jul.filter(d => d.aq !== 0 && d.location === selectLocation_3 && d.period === "before"), d => d.aq) - d3.mean(aq_before_after_jan_jul.filter(d => d.aq !== 0 && d.location === selectLocation_3 && d.period === "after"), d => d.aq), filter: d => d.location === selectLocation_3, lineHeight: 1, fontSize: 12, monospace: true, fontWeight: "normal" }), Plot.text([[1, 0]], { x: 1, y: 0, text: ["P-Value:"], fontStyle: "italic", lineHeight: 1, fontSize: 12, textAnchor: "start" }), Plot.text( aq_before_after_jan_jul, { x: 3, y: 0, text: d => d["t-test"], filter: d => d.location === selectLocation_3 && d["t-test"] !== null, fontSize: 13, lineHeight: 1, monospace: true, fontWeight: "bold", textAnchor: "start" } ), Plot.text( ["Probability of no change between before and after periods."], { x: 1, y: 2, //frameAnchor: "start", fontSize: 12, lineWidth: 32, textAnchor: "start", lineHeight: 1, //monospace: true, }) ], })37:T4f5,

	Jan-Jul 2019 average	Jan-Jul 2022 average	Change
Bethnal Green Road/Brick Lane	47.47	30.66	↓ 16.81
Paradise Row/Bethnal Green Road	47.24	31.33	↓ 13.93
Queensbridge/Hackney Road	45.97	32.04	↓ 15.91
Warner Place/Hackney Road	43.97	32.01	↓ 11.4
Tower Hamlets (excluding LTN areas)	48.31	37.17	↓ 11.13

38:T6a4,Plot.plot({ y: { label: "↑ Air quality (NO2 µg/m3)", grid: true }, x: { type: "time", label: "Month and year →", grid: true, thresholds: d3.utcMonth, tickFormat: d3.utcFormat("%b %y"), tickRotate: 90, line: true, tickPadding: 10 }, marks: [ Plot.lineY(air_quality_not_ltns, Plot.binX( {y: "mean"}, { x: "utctimestamp", y: "aq", sort: null, stroke: "black", strokeWidth: 1, opacity: 0.3, filter: (d) => d.aq !== 0, interval: d3.utcMonth })), Plot.linearRegressionY(air_quality_not_ltns, Plot.binX( {y: "mean"}, { x: "utctimestamp", y: "aq", sort: null, stroke: "black", strokeWidth: 1, opacity: 0.3, filter: (d) => d.aq !== 0, interval: d3.utcMonth })), Plot.lineY(air_quality_ltns, Plot.binX( {y: "mean"}, { x: "utctimestamp", y: "aq", sort: null, stroke: "#71da71", strokeWidth: 2, opacity: 0.4, filter: (d) => d.aq !== 0, interval: d3.utcMonth })), Plot.linearRegressionY(air_quality_ltns, Plot.binX( {y: "mean"}, { x: "utctimestamp", y: "aq", sort: null, fill: "green", opacity: 0.6, stroke: "#71da71", filter: (d) => d.aq !== 0, interval: d3.utcMonth })), // National target //Plot.ruleY([40],{stroke: "red", opacity: 0.2, strokeWidth: 3}) ], inset: 10, marginBottom: 85, width: 1240, height: 500 })39:T613,Plot.plot({ color: { type: "categorical", legend: false, scheme: "greys", //legend: "ramp" }, y: { label: "↑ Air quality (NO2 µg/m3)", grid: true }, x: { type: "time", label: "Month and year →", grid: true, thresholds: d3.utcMonth, tickFormat: d3.utcFormat("%b %y"), tickRotate: 90, line: true, tickPadding: 10 }, marks: [ Plot.rectY(air_quality, Plot.binX( {y: "mean"}, { x: "utctimestamp", y: "aq", sort: null, fill: "grey",//d3.mean(air_quality, d => d.aq), opacity: 0.5, filter: (d) => d.aq !== 0 && !d.month.includes("-15"), interval: d3.utcYear })), Plot.rectY(air_quality, Plot.binX( {y: "mean"}, { x: "utctimestamp", y: "aq", sort: null, fill: "grey",//d3.mean(air_quality, d => d.aq), opacity: 0.2, filter: (d) => d.aq !== 0 && !d.month.includes("-15"), interval: d3.utcMonth })), Plot.linearRegressionY(air_quality, Plot.binX( {y: "mean"}, { x: "utctimestamp", y: "aq", sort: null, stroke: "green", strokeWidth: 1, opacity: 0.9, filter: (d) => d.aq !== 0 && !d.month.includes("-15"), interval: d3.utcMonth })), // National target Plot.ruleY([40],{stroke: "red", opacity: 0.2, strokeWidth: 3}) ], inset: 10, marginBottom: 85, width: 640, height: 500 })3a:T624,Plot.plot({ color: { type: "categorical", legend: false, scheme: "greys", //legend: "ramp" }, y: { label: "↑ Air quality (NO2 µg/m3)", grid: true }, x: { type: "time", label: "Month and year →", grid: true, thresholds: d3.utcMonth, tickFormat: d3.utcFormat("%b %y"), tickRotate: 90, line: true, tickPadding: 10 }, marks: [ Plot.rectY(air_quality_ltns, Plot.binX( {y: "mean"}, { x: "utctimestamp", y: "aq", sort: null, fill: "green",//d3.mean(air_quality, d => d.aq), opacity: 0.4, filter: (d) => d.aq !== 0 && !d.month.includes("-15"), interval: d3.utcYear })), Plot.rectY(air_quality_ltns, Plot.binX( {y: "mean"}, { x: "utctimestamp", y: "aq", sort: null, fill: "green",//d3.mean(air_quality, d => d.aq), opacity: 0.2, filter: (d) => d.aq !== 0 && !d.month.includes("-15"), interval: d3.utcMonth })), Plot.linearRegressionY(air_quality_ltns, Plot.binX( {y: "mean"}, { x: "utctimestamp", y: "aq", sort: null, stroke: "green", strokeWidth: 1, opacity: 0.9, filter: (d) => d.aq !== 0 && !d.month.includes("-15"), interval: d3.utcMonth })), // National target Plot.ruleY([40],{stroke: "red", opacity: 0.2, strokeWidth: 3}) ], inset: 10, marginBottom: 85, width: 640, height: 500 })3b:T560,> *In the graphs above:* - *NO₂ measures for 2015 have been omitted as they only begin in May;* - *the annual average for 2022 may change as the data is partial and has not been bias-adjusted or annualised (which will reduce measures by approximately 25%);* - *where there are missing bars, no data has been collected — for example, no data was collected during the first Covid lockdown, starting March 2020.* The Government's ["National Air Quality Objective"]( https://uk-air.defra.gov.uk/assets/documents/Air_Quality_Objectives_Update.pdf) (or what we are calling the *national target*) is used to evaluate annual air quality measures, recognising there is likely to be variation over the year. Evidence of the relationship between annual average NO₂ and short term peak NO₂ shows that where annual average is below 60µg/m3, the hourly (1 hour mean) NO₂ air quality objective (‘200 µg/m3 not to be exceeded more than 18 times a year’) is unlikely to be exceeded (see this [DEFRA report](https://laqm.defra.gov.uk/documents/NO2relationship_report.pdf)). As none of the monitored sites in and around the Tower Hamlets LTNs come close to an annual mean of 60µg/m3, it is safe to discount any significant risk of these sites exceeding the 1 hour mean short term air quality objective to protect acute health risks. 3c:T4ea,Plot.plot({ color: { //type: "categorical", legend: false, scheme: "rdylgn", type: "diverging-symlog", pivot: 30, symmetric: true, reverse: true, //legend: "ramp" }, y: { label: "Air quality (NO2 µg/m3) for all LTN areas", grid: true }, x: { type: "time", label: "Month and year →", //grid: true, //thresholds: d3.utcMonth, tickFormat: d3.utcFormat("20%y") }, marks: [ Plot.rectY(air_quality_ltns, Plot.binX( {y: "mean"}, { x: "utctimestamp", y: "aq", sort: null, fill: "#9ce085", filter: (d) => d.aq !== 0, interval: d3.utcMonth })), Plot.linearRegressionY(air_quality_ltns, Plot.binX( {y: "mean"}, { x: "utctimestamp", y: "aq", sort: null, fill: "green", stroke: "green", filter: (d) => d.aq !== 0, interval: d3.utcMonth })), //Plot.linearRegressionY(air_quality, {x: "utctimestamp", y: "aq", filter: (d) => d.aq !== 0, interval: d3.utcMonth, fill: "aq", opacity: 0.6}), //Plot.ruleY([40],{stroke: "red", opacity: 0.2, strokeWidth: 3}) ], inset: 10, marginBottom: 45, width: 800 })3d:T8ee,

	2015	2016	2017	2018	2019	2020	2021
Bethnal Green Rd/ Brick Lane	46.98	45.54	44.28	35.64	36.58	27.40	26.33
Calvert Ave/Boundary Street	42.10	40.98	39.43	37.15	34.66	26.00	21.96
Colombia Rd/Gossett Street	38.46	37.48	38.37	34.30	32.74	24.90	21.45
Grove Rd/Old Ford Rd	47.05	47.78	45.12	42.53	40.49	27.50	26.83
Paradise Row/Bethnal Green Rd	49.64	44.07	41.17	41.18	36.01	28.10	28.07
Parmiter St/ Cambridge Heath Road				44.74	40.87	30.30	28.53
Queensbridge Rd/Hackney Rd				55.45	35.26	26.20	24.41
Roman Rd/Globe Road				36.21	34.13	25.80	26.82
Squirries St/Gosset St				38.35	37.55	27.10	25.43
Warner Place/Hackney Rd	42.01	41.15	40.19	37.94	35.44	25.50	22.54
Whitechapel High Street	72.24	63.55	61.51	61.16	47.84	33.90	37.70

3e:T8ff,locations = ["Ackroyd Drive", "Admirals Way", "Augusta St/Giraud St", "Ben Johnson Road", "Bethnal Green Rd/ Brick Lane", "Blair Street (End of Street)", "Bonner Road", "Bow Common Lane/St Paul's Way", "Bow Rd /Glebe Terrace", "Bow Rd/Alfred St", "Brick Lane/Princelet St", "Brodlove Lane", "Bromley High Street/ St Leonards", "Buckfast St/Bethnal Green Rd", "Calvert Ave/Boundary Street", "Cartwright Street", "Cascades, Westferry Road", "Cavell St/Stepney Way", "Chrisp Street/E India Dock Road ", "Columbia Rd/Gossett Street", "Commercial St/Calvin St", "Dellow St/The Highway", "Devas Street /Devons road", "Devons Road / Campbell Road ", "Dod St/Burdett Rd", "Dolphin Lane", "Fairfield Road/Tredegar Road ", "Fieldgate Street", "Finnis St/Three Colts Lane", "Ford Close/Roman Rd", "Globe Rd/Mile End Rd", "Grove Rd/Old Ford Rd", "Hale Street", "Hannibal Rd/Mile End Rd", "Harford St/Mile End Rd", "Hatfield Terrace/Fairfield Road", "John Smith Mews", "Jubilee Street/Commercial Rd", "Lawnhouse Close ", "Limeharbour", "Locksley St/St Paul's Way", "Manchester Road/East Ferry Road", "Manchester Road/Ollife Street ", "Mansell St", "Mast House Terrace", "Mile End Road Corner Bancroft Rd", "Millwall Park 1", "Millwall Park 2", "Morris/Barchester Street", "Narrow St/Limehouse Link", "Newport Avenue", "Paradise Row/Bethnal Green Rd", "Parmiter St/ Cambridge Heath Road", "Parnell Rd/Old Ford Rd", "Philpot St/Commercial Road", "Pitsea St/Commercial Rd", "Poplar High St/Cotton St", "Portree Street", "Prestons Road/ Coldharbour", "Queensbridge Rd/Hackney Rd", "Rhodeswell Rd", "Rhondda Grove/Mile End Rd", "Rich Street", "Roman Rd/Globe Road", "Sextant Avenue", "Seyssel Street", "Shirbutt St o/s Holy Family School", "Sidney St/Mile End Rd", "Squirries St/Gosset St", "St Katherine's Way", "St Stephen's Rd/Tredegar Rd", "Stepney Green", "TH Cemetery Park", "Thames Path Storers Quay", "Thoydon Rd", "Toynbee St/Commercial St", "Victoria Park (Co-location site 1)", "Victoria Park 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2f:{"id":"a6160198e9d9a000","slug":"air-quality-measurements-in-tower-hamlets","title":"Air Quality Measurements in Tower Hamlets","thumbnail":"476d25a55a2b16a65d35aa1e1dbd1aece61bdbaadda43e1fde4f1aa14e0126f4","access_level":"public","create_time":"$D2022-09-17T16:57:33.045Z","update_time":"$D2022-10-02T09:21:44.472Z","view_time":null,"first_public_time":"$D2022-09-18T11:20:50.088Z","fork":false,"stars":2,"starred":false,"owner":{"type":"team","id":"b2e8b22fd64f7967","login":"soss","name":"Save our Safer Streets","avatar_url":"https://avatars-next.observableusercontent.com/e586d4e6a8d1d3fbcc013290d7cc4d7072a949900c98f1ebe27f5d1605a32952","tier":"starter_2024"},"version":1761,"publish_version":null,"role":null,"authored":false,"authors":[{"type":"individual","id":"f2f890c11c9e8ce2","login":"soss","name":"Save our Safer Streets","avatar_url":"https://avatars-next.observableusercontent.com/e586d4e6a8d1d3fbcc013290d7cc4d7072a949900c98f1ebe27f5d1605a32952","tier":null}],"members":[{"type":"individual","id":"f2f890c11c9e8ce2","login":"soss","name":"Save our Safer Streets","avatar_url":"https://avatars-next.observableusercontent.com/e586d4e6a8d1d3fbcc013290d7cc4d7072a949900c98f1ebe27f5d1605a32952","tier":null,"role":"editor"}],"comments":[],"custom_thumbnail":true,"trashed":false,"lapsed":null,"subscribed":null,"forks":1,"collection":null,"type":"notebook","body":{"title":"Air Quality Measurements in Tower Hamlets","cells":[{"id":0,"value":"$31","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":647,"value":"$32","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":627,"value":"## Pollution levels are falling in the areas near to LTNs\n\nWe looked at the NO₂ measurements from diffusion tubes at 10 locations near to the Tower Hamlets LTNs. These were for:\n1. Columbia Rd/Gossett Street\n2. Calvert Ave/Boundary Street\n3. Bethnal Green Rd/ Brick Lane\n4. Grove Rd/Old Ford Rd\n5. Parmiter St/ Cambridge Heath Road\n6. Paradise Row/Bethnal Green Rd\n7. Queensbridge Rd/Hackney Rd\n8. Roman Rd/Globe Road\n9. Squirries St/Gosset St\n10. Warner Place/Hackney Rd.\n\nThe graph below shows that in all of these locations the trend is a fall in pollution (NO₂) levels. \n\n> *Choose a location below to see the downward (NO₂) trends in each area near to LTNs.*","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":190,"value":"viewof ltnLocation = Inputs.select(ltn_locations, {label: \"Choose location\", value: \"Squirries St/Gosset St\"})","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":41,"value":"Plot.plot({\n x: {\n //type: \"time\",\n label: \"Month and year →\",\n grid: true,\n tickFormat: d3.utcFormat(\"%b %y\")\n },\n y: {\n label: \"↑ Air quality (NO2 µg/m3) \" + ltnLocation,\n grid: true\n },\n marks: [\n Plot.rectY(air_quality, {x: \"utctimestamp\", y: \"aq\", filter: (d) => d.location === ltnLocation && d.period === \"before\" && d.aq !== 0, interval: d3.utcMonth, curve: \"catmull-rom\", marker: \"circle\", fill: \"steelblue\"}),\n Plot.rectY(air_quality, {x: \"utctimestamp\", y: \"aq\", filter: (d) => d.location === ltnLocation && d.period === \"after\" && d.aq !== 0, interval: d3.utcMonth, curve: \"catmull-rom\", marker: \"circle\", fill: \"orange\"}),\n Plot.linearRegressionY(air_quality, {x: \"utctimestamp\", y: \"aq\", filter: (d) => d.location === ltnLocation && d.aq !== 0, interval: d3.utcMonth, stroke: highlight, opacity: 0.6}),\n Plot.ruleY([40],{stroke: \"red\", opacity: 0.2, strokeWidth: 3})\n ],\n inset: 10,\n marginBottom: 45\n})","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":216,"value":"> *Above, the blue bars represent measurements taken before the LTNs were installed and the orange bars after. The green line is the trend for measurements between May 2015 and runs to July 2022. The red line is the UK national target (40 µg/m3).*","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":1178,"value":"If we look at the yearly NO₂ averages, we see these downward trends in pollution confirmed. In Table 1, the annual averages in each location fall below the national target of 40 µg/m3 by 2021.\n\nWe've had to estimate the final annual averages for 2022 because we don't have values from August to December in this year (this analysis was conducted in September 2022). To make these estimates, we have used the August to December figures from 2021. This means the 2022 averages could change. We believe it is important that the Council wait for verified full year data before making a decision on the schemes.\n\n> *Values in Table 1 are raw NO₂ values. We include Whitechapel High Street (bottom row) as a point of comparison.*","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":635,"value":"

*Pre-bias adjusted and annualised values*

","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":297,"value":"$33","pinned":false,"hidden":false,"mode":"html","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":276,"value":"Plot.plot({\n height: 60,\n marginBottom: 6,\n marginTop: 5,\n marks: [\n Plot.text(\n [\"Table 1. Average monthly NO2 levels between 2015 to 2022 for locations near LTNs.\"],\n {\n frameAnchor: \"top\",\n fontSize: 12,\n //lineWidth: 20,\n //textAnchor: \"start\",\n lineHeight: 1.3,\n // monospace: true,\n //clip: true\n }\n ),\n Plot.text(\n [\"* 2022 values are calculated using monthly values to July 2022 and August to December figures from 2021.\"],\n {\n frameAnchor: \"bottom\",\n fontSize: 12,\n lineWidth: 38,\n //textAnchor: \"start\",\n lineHeight: 1.3,\n // monospace: true,\n //clip: true\n }\n )\n ],\n})","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":637,"value":"The results in Table 1 show further improvement if we estimate the bias-adjusted and annualised values for 2022 (for further information about adjusting for bias see this [helpful webpage](https://lovecleanair.org/about-air-quality/how-pollutants-measured/co-location-sites-bias-adjustment/)). In Table 2, we've followed the guidance accompanying the Tower Hamlets dataset, and reduced the 2022 values by 25%. We've then compared these estimates with bias-adjusted and annualised values from previous years.\n\nAgain, it's important to note the 2022 figures are estimates and calculated as we have described above.\n\nWith these adjusted figures, annual averages in each location fall below the national target of 40 µg/m3 by 2020.","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":1163,"value":"

*Bias adjusted and annualised values*

","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":299,"value":"$34","pinned":false,"hidden":false,"mode":"html","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":306,"value":"Plot.plot({\n height: 74,\n marginBottom: 6,\n marginTop: 5,\n marks: [\n Plot.text(\n [\"Table 2. Bias adjusted and annulised average monthly NO2 levels between 2015 to 2022 (for locations near LTNs.)\"],\n {\n frameAnchor: \"top\",\n fontSize: 12,\n lineWidth: 38,\n //textAnchor: \"start\",\n lineHeight: 1.3,\n // monospace: true,\n //clip: true\n }\n ),\n Plot.text(\n [\"* 2022 values are calculated using monthly values to July 2022 and August to December figures from 2021.\"],\n {\n frameAnchor: \"bottom\",\n fontSize: 12,\n lineWidth: 38,\n //textAnchor: \"start\",\n lineHeight: 1.3,\n // monospace: true,\n //clip: true\n }\n )\n ],\n})","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":1394,"value":"In sum, air quality levels have improved in all areas surrounding Tower Hamlets' LTNs. Annual averages have been falling below the National target of 40 µg/m3 for 2/3 years.","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":1210,"value":"## Pollution levels have fallen since the LTNs were installed\n\nTo look at the possible impact Tower Hamlets' LTNs have had on air quality, we compared like-for-like periods before and after they were installed. We've based our analysis on Tower Hamlets' LTNs being operational from 1st July 2021 (though some of the new road layouts were being modified well after this date).\n\nFor each of the locations near to LTNs, we compared the first 7 months in 2019 (Jan-Jul 2019) and the first 7 months in 2022 (Jan-Jul 2022). We also made the same before and after comparison for Tower Hamlets as a whole.\n\nFor the table below, we aggregated the No₂ measures for all ten of the locations near to LTNs. We've then compared the fall in pollution in the LTN areas (in aggregate) with Tower Hamlets as a whole. We see that the fall for the LTN areas were greater (a fall of 14.58 in the LTN areas compared to 11.13 for Tower Hamlets).","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":1045,"value":"\n\n\n \n \n \n \n \n \n\n\n \n \n \n \n \n \n \n \n \n \n \n \n\n

	Jan-Jul 2019 average	Jan-Jul 2022 average	Change
LTN areas	48.32	33.74	↓ 14.58
Tower Hamlets (excluding LTN areas)	48.31	37.17	↓ 11.13

","pinned":false,"hidden":false,"mode":"html","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":1231,"value":"We can see these aggregate falls born out when we compare the before and after periods for individual locations. In all cases, there have been falls in pollution levels between the before and after periods. \n\nIf we compare the NO₂ measurements in the before and after periods using a statistical test known as a *t-test*, we find the falls in pollution levels are statistically significant (p-value < 0.05) in all locations except Bethnal Green Road/Brick Lane. For this location there was no statistical difference — in other words, even though there was a decline there was no significant change.\n\n> *To see comparisons between the before and after periods for the individual locations near to LTNs and for Tower Hamlets, choose from the \"*Choose location*\" option below.*","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":352,"value":"viewof selectLocation_3 = Inputs.select(ltn_locations_and_TH, {label: \"Choose location\", value: \"Paradise Row/Bethnal Green Rd\"})","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":347,"value":"$35","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":522,"value":"$36","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":1227,"value":"## Pollution levels fall more on Hackney Road and Bethnal Green Road than Tower Hamlets as a whole\n\nWe also wanted to check whether the LTNs have been impacting air quality on nearby major arteries in and out of London. \n\nTo do this, we compared the declines in NO₂ levels on Hackney Road and Bethnal Green Road with Tower Hamlets as a whole. \n\nIn the table below, we see the comparisons between the before and after periods for each location we have measurements for on Hackney Road and Bethnal Green Road, and for Tower Hamlets.\n\nWhat we find is that the declines in NO₂ levels are greater on Hackney Road and Bethnal Green Road. In other words, the LTNs don't appear to have exacerbated air quality levels on nearby major arteries.","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":1267,"value":"$37","pinned":false,"hidden":false,"mode":"html","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":1422,"value":"Plot.plot({\n height: 40,\n marginBottom: 6,\n marginTop: 5,\n marks: [\n Plot.text(\n [\"Table 3. Before and after comparisons for main artery roads near to LTNs, and for Tower Hamlets as a whole.\"],\n {\n frameAnchor: \"top\",\n fontSize: 12,\n lineWidth: 38,\n //textAnchor: \"start\",\n lineHeight: 1.3,\n // monospace: true,\n //clip: true\n }\n )\n ],\n})","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":623,"value":"## Tower Hamlets Pollution levels have fallen since 2015\n\nFor the bigger picture, we wanted to see how air quality has been doing across Tower Hamlets as a whole, and to draw out comparisons with the areas near to the borough's LTNs. \n\nBelow, we've plotted the average monthly NO₂ levels across Tower Hamlets (grey line) and the average monthly NO₂ levels for those streets nearest to LTNs (green line). Also included are trend lines (the straight grey and green lines) for both sets of averages.\n\nFrom the trend lines, we see that NO₂ levels are falling for Tower Hamlets and for the locations near to LTNs. In LTN-associated areas, the rate of decline is greater indicated by the green line's steeper, falling slope.","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":846,"value":"Plot.legend({\n color: {\n type: \"categorical\",\n domain: [\"Tower Hamlets\", \"LTN areas\"], \n range: [\"gray\", \"#71da71\"]\n }\n})","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":677,"value":"$38","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":820,"value":"> *In the above graph, the green line is the average of monthly measurements taken from diffusion tubes at 10 locations: *Columbia Rd/Gossett Street*, *Calvert Ave/Boundary Street*, *Bethnal Green Rd/ Brick Lane*, *Grove Rd/Old Ford Rd*, *Parmiter St/ Cambridge Heath Road*, *Paradise Row/Bethnal Green Rd*, *Queensbridge Rd/Hackney Rd*, *Roman Rd/Globe Road*, *Squirries St/Gosset St*, *Warner Place/Hackney Rd*.*\n\n> *The grey line represents the monthly averages for all diffusion tubes across Tower Hamlets, except for the locations above.*","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":911,"value":"## Average pollution levels fall below the national target\n\nIn the bar graph, we've plotted the Tower Hamlets NO₂ monthly (thin light grey) and yearly (wider darker grey) averages and both the air quality trend line (green) and national target (red).\n\nWe can see lower annual levels from July 2021 that meet the [\"National Air Quality Objective\"]( https://uk-air.defra.gov.uk/assets/documents/Air_Quality_Objectives_Update.pdf) or national target of 40 µg/m3.\n\nThere are likely to be two drivers behind this trend, one, the launch of London's *ultra low emission zone* (ULEZ) in April 2019 and, two, the Covid pandemic and the different levels of lockdown between March 2020 and March 2021.","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":952,"value":"Plot.legend({\n color: {\n type: \"categorical\",\n domain: [\"National target\", \"Air quality monthly average\", \"Trend for Tower Hamlets\"], \n range: [\"red\", \"grey\", \"#71da71\"]\n }\n})","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":893,"value":"$39","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":949,"value":"> *In the graphs above:*\n - *NO₂ measures for 2015 have been omitted as they only begin in May;*\n - *the annual average for 2022 may change as the data is partial and has not been bias-adjusted or annualised (which will reduce measures by approximately 25%);*\n - *where there are missing bars, no data has been collected — for example, no data was collected during the first Covid lockdown, starting March 2020.*\n\nIf we compare the averages for Tower Hamlets (above) against the 10 locations near to the LTNs (graph below), we see there are lower averages from July 2021. We also see annual average levels fall below the National target of 40 µg/m3 from Jan 2020.\n\nIn like-for-like periods between July 2021 and July 2022 (where the impacts of the *ULEZ* and Covid are proportionate), we see air quality in LTN areas compare more favourably against the national target.","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":955,"value":"Plot.legend({\n color: {\n type: \"categorical\",\n domain: [\"National target\", \"Air quality monthly average\", \"Trend for LTN areas\"], \n range: [\"red\", \"green\", \"#71da71\"]\n }\n})","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":945,"value":"$3a","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":1090,"value":"$3b","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":1697,"value":"## See more analysis\n\n- [Ambulance response times](https://i.heartbg.uk/LAS-response-time-analysis)\n- [Fire service response times](https://i.heartbg.uk/LFB-response-time-analysis)","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":8,"value":"## Appendix","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":222,"value":"","pinned":false,"hidden":false,"mode":"html","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":715,"value":"$3c","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":861,"value":"Above, the darker bars indicate higher levels of pollution. The horizontal red bar is the nation target (40 µg/m3 Nitrogen Dioxide). Where no data has been collected there are missing bars — for example no data was collected during the first Covid lockdown, starting March 2020.","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":103,"value":"viewof location = Inputs.select(locations, {label: \"Choose location\"})","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":879,"value":"Plot.legend({\n color: {\n type: \"categorical\",\n domain: [\"National target\", \"Monthly air quality level\", \"Trend for LTN area\"], \n range: [\"red\", \"grey\", \"#71da71\"]\n }\n})","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":14,"value":"Plot.plot({\n color: {\n type: \"categorical\",\n nice: true,\n legend: false,\n scheme: \"greys\",\n //reverse: true,\n },\n y: {\n label: \"↑ Air quality (NO2 µg/m3) on \" + location,\n grid: true\n },\n x: {\n type: \"time\",\n label: \"Month and year →\",\n grid: true,\n thresholds: d3.utcMonth,\n tickFormat: d3.utcFormat(\"%b %y\")\n },\n marks: [\n Plot.rectY(air_quality, {x: \"utctimestamp\", y: \"aq\", filter: (d) => d.location === location && d.aq !== 0, interval: d3.utcMonth, fill: \"aq\"}),\n Plot.linearRegressionY(air_quality, {x: \"utctimestamp\", y: \"aq\", filter: (d) => d.location === location && d.aq !== 0, interval: d3.utcMonth, stroke: \"green\", opacity: 0.6}),\n Plot.ruleY([40],{stroke: \"red\", opacity: 0.2, strokeWidth: 3})\n ],\n inset: 10,\n marginBottom: 45,\n width: 800\n}\n)","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":239,"value":"$3d","pinned":false,"hidden":false,"mode":"html","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":141,"value":"operationalDate = new Date('2021-07-01') // Assumed date LTNs installed","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":985,"value":"TH_mean = d3.mean(air_quality.filter(d => d.aq !== 0), d => d.aq).toFixed(2)","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":998,"value":"TH_mean_before_period = d3.mean(aq_before_after_jan_jul.filter(d => d.aq !== 0 && d.location === selectLocation_3 && d.period === \"before\"), d => d.aq)","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":1006,"value":"TH_mean_after_period = d3.mean(aq_before_after_jan_jul.filter(d => d.aq !== 0 && d.location === selectLocation_3 && d.period === \"after\"), d => d.aq)","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":1342,"value":"TH_mean_change = TH_mean_before_period - TH_mean_after_period","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":1009,"value":"ltn_mean_before_period = d3.mean(air_quality_ltns.filter(d => d[\"test-period\"] === \"before-period\" && d.aq !== 0), d => d.aq)","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":1015,"value":"ltn_mean_after_period = d3.mean(air_quality_ltns.filter(d => d[\"test-period\"] === \"after-period\" && d.aq !== 0), d => d.aq)","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":1043,"value":"ltn_change = ltn_mean_before_period - ltn_mean_after_period","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":988,"value":"not_ltn_mean = d3.mean(air_quality_not_ltns.filter(d => d.aq !== 0), d => d.aq)","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":1018,"value":"not_ltn_mean_before_period = d3.mean(air_quality_not_ltns.filter(d => d[\"test-period\"] === \"before-period\" && d.aq !== 0), d => d.aq)","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":1023,"value":"not_ltn_mean_after_period = d3.mean(air_quality_not_ltns.filter(d => d[\"test-period\"] === \"after-period\" && d.aq !== 0), d => d.aq)","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":1041,"value":"not_ltn_change = not_ltn_mean_before_period - not_ltn_mean_after_period","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":10,"value":"air_quality = FileAttachment(\"air_quality_v3@3.csv\").csv({typed: true})","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":706,"value":"air_quality_ltns = air_quality.filter(d => ltn_locations.includes(d.location))","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":765,"value":"air_quality_not_ltns = air_quality.filter(d => !ltn_locations.includes(d.location))","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":11,"value":"air_quality_averages = FileAttachment(\"air_quality_v3@3.csv\").csv({typed: true})","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":343,"value":"aq_before_after_jan_jul = FileAttachment(\"aq_before_after_Jan_jul@3.csv\").csv()","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":99,"value":"function highlight(d) {\n var color = \"green\"\n return color;\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":119,"value":"$3e","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":174,"value":"ltn_locations = [\n\"Columbia Rd/Gossett Street\", \"Calvert Ave/Boundary Street\", \"Bethnal Green Rd/ Brick Lane\", \"Grove Rd/Old Ford Rd\", \"Parmiter St/ Cambridge Heath Road\", \"Paradise Row/Bethnal Green Rd\", \"Queensbridge Rd/Hackney Rd\", \"Roman Rd/Globe Road\", \"Squirries St/Gosset St\", \"Warner Place/Hackney Rd\"]","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":1257,"value":"ltn_locations_and_TH = [\n\"Columbia Rd/Gossett Street\", \"Calvert Ave/Boundary Street\", \"Bethnal Green Rd/ Brick Lane\", \"Grove Rd/Old Ford Rd\", \"Parmiter St/ Cambridge Heath Road\", \"Paradise Row/Bethnal Green Rd\", \"Queensbridge Rd/Hackney Rd\", \"Roman Rd/Globe Road\", \"Squirries St/Gosset St\", \"Warner Place/Hackney Rd\", \"Whitechapel High St (KFC)\", \"Tower Hamlets\"]","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"}],"files":"$W3f","stdlib":"1","titling":"auto"}} 30:"$2f:body"