Downtown Vancouver and Kitsilano ranked first and second for the highest levels of nitrogen dioxide of 32 B.C. locations tested in 2013.

The information is included in the B.C. Lung Association's "state of the air" report, which will be presented to the Metro Vancouver environment and parks committee on Thursday (July 3).

"Nitrogen dioxide (NOx) is a reddish-brown gas with a pungent odour that is a product of high-temperature combustion sources such as transportation and industry," the report states. "Short-term exposures to elevated levels are linked to increased respiratory symptoms and there are a growing number of studies linking NOx exposure to more serious health effects including cardiovascular, mortality, cancer and reproductive effects."

Downtown Vancouver and Kitsilano were the only B.C. areas that recorded between 15 to 18 parts per billion.

Rounding out the top 10 in order were Burnaby South, North Delta, Richmond South, Port Moody, North Vancouver-Mahon, Burnaby-Kensington Park, Coquitlam, and Prince George Plaza.

None of the areas exceeded Metro Vancouver's objective of 21 parts per billion or the national objective of 32 parts per billion.

While the downtown core of Vancouver posted the worst result for NOx levels, it ranked best in ground-level ozone, otherwise known as smog.

The report describes ground-level ozone as "a gaseous pollutant that is formed in the air from reactions involving oxides of nitrogen (NOx) and hydrocarbons in the present of sunlight".

"In 2013, ozone levels were generally low across the province," the report notes. "No sites exceeded the level of the new national standard of 63 ppb (based on 4th highest daily 8-hour maximum)."

Kelowna had the highest concentration of smog in B.C., followed by Hope. "The highest hourly concentration was recorded on July 1 in Agassiz when ozone levels peaked at 73 ppb."

The highest annual concentration of sulphur dioxide occurred in Trail, which was the only community to exceed the provincial annual objective of 10 parts per billion.

Both Trail and Port Alice exceeded the short-term provincial objective of 170 parts per billion of sulphur over one-hour periods.

High sulphur levels are associated with industrial facilities.

Trail has a zinc and lead smelter; Port Alice has a pulp mill.