Air quality

The quality of the air we breathe is important to our health. The main issue is winter-time smog due to wood-burning.

We monitor air quality in both Richmond and Nelson.

Air quality data

Click on a marker on the map to see recent data.

Sites

Disclaimer for Air Quality Data

Measuring Air Quality

We monitor air quality by measuring the amount of small particles in the air - the technical term is 'particulate matter smaller than 10 microns', or PM10. The National Environmental Standard for air quality requires that fine particles (finer than 10 micron; called PM10) must not average over 50 µg/m3 over a 24-hour period for more than one day each year.

We need to decrease the number of exceedences to no more than 1. This is because there is a very significant increase in risk to human health above this level.

Richmond has been the only place in Tasman where breaches of this standard are known to occur and this is the only designated airshed requiring improvement under this legislation.

We measure air quality in Richmond throughout the year to determine the volume of small particles in the air.

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). 

We also measure the weather conditions in Richmond and Nelson, as wind direction, wind speed, rainfall, temperature and solar radiation may affect how air contaminants are dispersed, and where they build up. This is important in the process of managing Richmond’s air quality problem during winter. This will help us understand if air quality is improving for a certain meteorological condition.

Method for Measuring Air Quality

To measure air quality in Richmond, we use a Beta Attenuated Monitor (BAM) to find out how much suspended particulate (PM10) is in the air. We also use a Partisol for specific investigations in Richmond and other towns.

A small pump in the instrument sucks air through a size-selective inlet and through a filter at a constant rate. A constant source of high energy electrons (beta particles) is beamed through the filter where the PM10 deposit is collected. The number of these electrons is reduced (attenuated) by the PM10 deposit on the filter at a rate directly related to particulate mass (weight) which is then calculated. Because the machine knows how much air was sucked through the filter the concentration of PM10 in outside (ambient) air can be calculated.

The information from the BAM is then automatically sent to Tasman District Council via the phone lines along with wind speed, wind direction and temperature data. Data you see on the website is raw data directly fed from the instrument.

The 1- minute or hourly PM10 readings are averaged into a daily reading, and are also displayed as daily averages for the past week and winter season.

State of air quality in Tasman District

Tasman District’s air quality is generally good, but wood-burning releases too many fine particles into the air, resulting in winter-time smog. This is a particular problem in Richmond. Preliminary surveys of Motueka, Brightwater and Wakefield suggest that air quality in those towns is good, apart from a small area of Brightwater.

Other air quality issues in Tasman District are:

  • Rural outdoor burn-offs - many people call council about this issue. Burn-offs occur mainly in early winter and particularly on horticultural land;
  • Major discharges from industry - information gathered as part of conditions of resource consents for discharge to air show no significant effects at this point;
  • Pesticide spray drift – these issues are generally localised and limited to particular sites;
  • Greenhouse gas emissions - emissions of carbon dioxide and methane are managed at a national level by the Ministry for the Environment.