Queen's Park community air quality monitoring
NO₂ Monitoring Map
Choose a survey date, then select a monitoring point to see the result, change from the previous survey and the site's historical trend.
Selected survey
Location comparison
Select a monitoring point on the map to highlight that location in the chart.
Percent of limit is calculated against the 40 µg/m³ annual mean legal limit. Individual diffusion-tube survey periods are not, by themselves, an annual compliance assessment.
Monitoring location trend
NO₂ trend over time
Choose a monitoring location to show its available results through time.
Points use the same concentration colours as the map. The dashed line marks 40 µg/m³, the annual mean legal limit. Missing or unverified results are shown as gaps. Hover over a point to see the percentage of the limit and change from the previous survey.
Long-term performance
Best & worst performing locations
Ranked by the long-term NO₂ trend using the actual survey dates. A downward trend indicates improving concentrations.
Best performing
Worst performing
Performance is based on the slope of each site's long-term trend, not simply its latest concentration. Click a location to open it in the site trend chart above.
Monitoring network over time
Survey trend analysis
Compares the network median NO₂ concentration between verified monitoring rounds.
The dashed line shows the long-term trend in verified network median NO₂, calculated using actual survey dates.
| Survey | Median NO₂ | Difference | Change | Direction |
|---|
Each survey uses valid outdoor monitoring results only. Improving means the network median is at least 5% lower than the previous verified survey; deteriorating means at least 5% higher; changes within ±5% are shown as stable.
Verified outdoor monitoring rounds
Best & worst performing surveys
Compare the three lowest and highest network median NO₂ concentrations, plus the largest changes from the previous verified survey.
Lowest median NO₂
Highest median NO₂
Largest improvements
Largest deteriorations
Only verified rounds with valid outdoor results are included. Medians compare different rounds, whose site coverage may vary; changes are relative to the previous verified round. Select an individual survey to update the map, or select all three in a category to highlight them together in the chart and survey-round table. The map continues to display one survey at a time.