airQual: exploration of air quality data

Poor air quality is well known to have both chronic (long term) and acute (short term) impacts on health. Air quality is also a useful indicator of traffic and other combustion patterns - i.e. energy use for different purposes at different times of day.

Southampton (UK)

Covid 19 lockdown analysis (Spring 2020)

We update this mini-report on a regular basis. These are the most recent plots for:

• NO2 plot: weekends notably lower <- less travel? Weekdays possibly lower but clearly still ’essential worker’ travel especially mid-week? Notice it started 1 week before true lockdown
• NOx plot: as per NO2?
• SO2 plot: Possibly similar to NO2 but…
• Ozone plot: much more affected by weather (sunny first lockdown weekend)?
• PM10 plot: as for NO2 but less noticeable the week before lockdown. But also possibly weather effect?
• PM2.5 plot: much more obvious lockdown but not pre-lockdown effect. But also possibly weather effect and even maybe a sensor/measurement effect? The AURN data here has not yet been ratified.

Analysis snapshots:

• Snapshot 18/6/2020 of the above analysis for BBC South.
• Snapshot 30/4/2020 of the above analysis, some of which was used in:
  • Anderson, Ben and Dirks, Kim (2020) A preliminary analysis of changes in outdoor air quality in the City of Southampton during the 2020 COVID-19 outbreak to date: a response to DEFRA’s Call for Evidence1 on Estimation of changes in air pollution emissions, concentrations and exposure during the COVID-19 outbreak in the UK. Southampton. Universty of Southampton This was a response to a DEFRA call for evidence.

General Analysis (pre 2020)

Southampton homes tend to rely on reticulated (mains) gas, electricity and in some areas, district heating. However gas boilers, woodburners and (relatively rare) coal fires are known sources of pollutants so heating systems may also be a contributor to poor air quality in Southampton alongside fossil-fuel based transport.

Data sources:

• Directly: from http://southampton.my-air.uk/ although this site is now mostly inactive. Plots and data also available from http://www.hantsair.org.uk/hampshire/asp/home.asp?la=Southampton;
• Indirectly: Two of the Southampton sites also feed to http://uk-air.defra.gov.uk/openair/R_data/ and the data can be downloaded using ōpenair::importAURN(). We explain which source we use when and why in the analysis.

NB: The AURN data undergoes a processes of ratification with a lag of about 6 months. Data less than 6 months old will not have undergone this process.

AURN data is (c) Crown 2020 copyright Defra via https://uk-air.defra.gov.uk, licenced under the Open Government Licence (OGL).

• Initial exploratory analysis - simple & interactive plots, can be slow to load; just uses southampton.my-air.uk
• Further exploratory analysis - uses the excellent openair R package
• Further exploratory analysis - uses AURN data downloaded via the excellent openair R package and SSC data. They mostly agree…
• extracting data for modelling & forecasting
• wind and pollution roses using the excellent openair R package and AURN data.

New Zealand

See https://www.mfe.govt.nz/air

In contrast to Southampton, New Zealand homes use a mixture of solid (coal/wood), electric (fueled by hydro/coal/gas/geothermal/wind) and reticulated (mains) / bottled gas heating. The prevalance of solid fuels, especially in regions which suffer winter temperature inversions is a particular problem.

As a result, switching to low emissions forms of heating (electric) and/or increasing insluation (or building to Passive house standards) will both reduce GHG emissions and improve air quality. As a consequence health impacts and costs are reduced - an excellent example of the co-benefits of de-carbonising heat. Rather than non-energy energy policy, we therefore have non-health health policy…

Of course, as elsewhere, fossil-fuel based transport is also a major contributor to poor air quality.

• Data sources: https://data.mfe.govt.nz/data/category/air/
• Data files: mfe-pm10-concentrations-200617-CSV and pm10-concentrations-200617.csv
• Initial exploratory analysis (does not yet use the excellent openair R package)
• Focus on Dunedin

Comparative

Southampton and Dunedin have much in common:

• deep water port relatively close to the CBD
• major transport routes bisecting the city
• major flows of commuters, passengers & freight to/from and through the city
• maritime temperate climate
• substantial student population

How does their air quality compare?

#YMMV