Nelson City measures smoke (PM10) at two sites, one on St Vincent St in Nelson (Airshed A), and the other on Blackwood St in Tahunanui (Airshed B). The results from monitoring are averaged over a 24 hour period (midnight to midnight) and compared against the National Air Quality Standard for PM10 which is 50 micrograms per cubic metre (µg/m3).
A high pollution event is one where the 24 hour average concentration of PM10 is greater than 50 µg/m3. The National Environmental Standard requires that by the year 2020 there are no more than one high pollution events per year in a monitored airshed.
| Location | 2013 | 2014 | 2015 | 2016 | 2017 | 2018 | 2019 | 2020 | 2021 | 2022 |
| Airshed A (Victory Square) | 9 | 2 | 1 | 0 | 1 | 2 | 0 | 0 | 0 | 0 |
| Airshed B (Tahunanui) | 1 | 1 | 0 | 1 | 3 | 0 | 2 | 0 | 0 | 0 |