Combining geographies: NO2
Gas boilers are responsible for several types of pollution: carbon monoxide is particularly dangerous indoors and can kill or seriously poison inhabitants. A high concentration of gas boilers seriously impacts air quality, particularly in cities. For example, in London in 2010, gas boilers contributed 21% of the NO2 pollution, second after transportation, which accounted for about 50%. In these areas, replacing gas boilers with electric alternatives brings more benefits than in others by reducing diseases and mortality in children and adults.
The map shows NO2 concentrations in the UK, where www.nomoregas.org can be more useful.
By overlapping technical/architectural knowledge and urban and geographic information, we could now design more granular policies to capture maximum advantages. For example, heat batteries and other electric alternatives to gas boilers could be incentivised in dense urban areas.
At the same time, when discussing curtailment, we noted how installing thousands of heat batteries in some areas of the North and Scotland would save the government and everyone energy and money.
The combination of these two geographies forms a National (albeit still partial) map of areas where transitioning away from gas should be favoured or incentivised.
 According to the government, every year, “4,000 people go to A&E, 200 people are hospitalised, and there are around 50 deaths in England and Wales”. https://www.gov.uk/government/news/carbon-monoxide-poisoning-sends-4-000-people-to-a-e-each-year  I suspect now the proportion will be a lot higher, thanks to the reduced pollution from transport (The Mayor of London has invested a lot into this campaign and policy).  To see the NO2 maps visit https://naei.beis.gov.uk/mapping/mapping_2020/6_large.png