Air Data

Ground-level (tropospheric) ozone (O3) exists at a natural background level but is also produced when nitrogen oxides (NOx) and volatile organic compounds from vehicle emissions, petrol fumes, industrial processes solvents, and other human-made sources react in the presence of sunlight. It is the primary component of photochemical smog.
Ozone also occurs naturally in the stratosphere, where it protects us from ultraviolet radiation – this ozone occasionally can mix downwards to ground level.
Because sunlight and warmth are required for the chemical reactions that form ground-level ozone, peak concentrations often occur in summer when daylight hours are longer and temperatures are higher. Since the precursors for ozone can travel downwind from their sources before they react with sunlight, ozone concentrations can be high many kilometres from the precursor emissions’ sources.
Exposure to high concentrations of ozone can cause respiratory health problems and is linked to cardiovascular health problems and mortality. It can also damage vegetation.
More information on this dataset and how it relates to our environmental reporting indicators and topics can be found in the attached data quality pdf.

Nitrogen dioxide (NO2) is a gas that is harmful to human health, ecosystems, and plants (US EPA, 2008). It can be emitted directly into the air but is often formed as a secondary pollutant when nitric oxide (NO) emissions react with other chemicals. It also contributes to the formation of secondary particulate matter (PM) and ozone, which have their own health impacts. In New Zealand, motor vehicles are the main human-made source of nitrogen oxides (NOx), the collective term for NO2 and NO. Because nitrogen dioxide concentrations are closely associated with vehicle emissions, it can be used as a proxy for other motor-vehicle pollutants such as benzene, carbon dioxide, and carbon monoxide.
Human exposure to high nitrogen dioxide concentrations causes inflammation of the airways and respiratory problems, particularly asthma. Nitrogen dioxide causes leaf injury in plants exposed to high levels. It also contributes to forming secondary particulate matter and ozone, which have their own health impacts.
We report on observed nitrogen dioxide concentrations from 13 regional council and unitary authority monitoring sites. Council and unitary authority data are measured using regulatory-compliant monitors that can be directly compared with health guidelines.
More information on this dataset and how it relates to our environmental reporting indicators and topics can be found in the attached data quality pdf.

Sulphur dioxide (SO2) is a highly reactive gas formed when fuels containing sulphur, such as coal or petrochemical products (including high-sulphur ship fuel), are burned. It is also produced from industrial processes such as superphosphate fertiliser production and smelting sulphur-containing metal ores. Geothermal and volcanic gases are the main natural sources of sulphur dioxide.
When inhaled, sulphur dioxide is associated with respiratory problems such as bronchitis. It can aggravate the symptoms of asthma and chronic lung disease and cause irritation to eyes. On days with higher sulphur dioxide levels, hospital admissions for cardiac disease and mortality increase. In ecosystems, it can injure vegetation, acidify water and soil, and affect biodiversity.
More information on this dataset and how it relates to our environmental reporting indicators and topics can be found in the attached data quality pdf.

Black carbon is a particle, often in the PM2.5 or ultra-fine size range, which is emitted from combustion sources and is commonly known as soot. In New Zealand most black carbon is emitted from vehicles (especially diesel vehicles), burning wood and coal for home heating, and outdoor burning. Both long and short-term exposure to black carbon is linked to serious health effects, such as respiratory and cardiovascular disease, cancer, and premature death (World Health Organization (WHO), 2013).
Black carbon warms the climate globally and regionally because it is efficient at absorbing energy from sunlight. Black carbon also increases ice and snow melt when deposited on these surfaces, darkening them and lowering albedo (proportion of light that is reflected) so they absorb more solar energy (Ramanathan & Carmichael, 2008).
More information on this dataset and how it relates to our environmental reporting indicators and topics can be found in the attached data quality pdf.