Air quality standards

Air quality is measured by comparing against a range of health-effects based standards. This page gives information about what this means.

Air Quality Standards and Objectives

Standards for air pollution are concentrations over a given time period that are considered to be acceptable in the light of what is known about the effects of each pollutant on health and on the environment. They can also be used as a benchmark to see if air pollution is getting better or worse.

An exceedance of a standard is a period of time (which is defined in each standard) where the concentration is higher than that set down by the standard. In order to make useful comparisons between pollutants, for which the standards may be expressed in terms of different averaging times, the number of days on which an exceedance has been recorded is often reported. An objective differs from a standard by accounting for achievability and sets a target date by which a standard must be achieved and often sets a specific number of exceedances of the standard that must not be exceeded.

The standards and Objectives adopted by the Government of Gibraltar are closely associated with the Limit Values and Target Values laid down in European air quality Directives. The objectives adopted in Gibraltar are based on the Public Health (Air Quality Limit Values) Rules 2002 as amended by the Public Health (Air Quality Limit Values) (Amendment) Rules 2002 and the Public Health (Air Quality) (Ozone) Rules 2004 for the purpose of Local Air Quality Management. These Air Quality Rules have adopted into Gibraltar law the Limit and Target values required by EU Daughter Directives on Air Quality.

A summary of the current Gibraltar Air Quality Objectives is provided here.

Summary of Objectives

Pollutant Objective Measured as To be achieved by
Benzene 5 µg m-3 Annual Mean 1 January 2010
Carbon monoxide 10.0 mg m-3 Maximum daily running 8 Hour Mean 1 January 2005
Lead 0.5 µg m-3 Annual Mean 1 January 2005
Nitrogen dioxide 200 µg m-3
Not to be exceeded more than 18 times per year
1 Hour Mean 1 January 2010
40 µg m-3 Annual Mean 1 January 2010
Nitrogen Oxides** (V) 30 µg m-3 Annual Mean 19 July 2001
Ozone 120 µg m-3 Running 8 hour Mean
Daily maximum of running 8 hr mean not to be exceeded more than 10 times per year. 25 times per calendar year averaged over 3 years
1 January 2010
Particlesa
(PM10)
(gravimetric)
50 µg m-3
Not to be exceeded more than 35 times per year
Daily Mean 1 January 2005
40 µg m-3 Annual Mean 1 January 2005
Sulphur dioxide 350 µg m-3
Not to be exceeded more than 24 times per year
1 Hour Mean 1 January 2005
125 µg m-3
Not to be exceeded more than 3 times per year
24 Hour Mean 1 January 2005
(V) 20 µg m-3 Annual Mean 19 July 2001
(V) 20 µg m-3 Winter Mean (01 October - 31 March) 19 July 2001
Arsenic 6 ng m-3 Annual Mean 31 December 2012
Cadmium 5 ng m-3 Annual Mean 31 December 2012
Nickel 20 ng m-3 Annual Mean 31 December 2012
PAH
(Benzo[a]pyrene***)
1 ng m-3 Annual Mean 31 December 2012

Notes:
a. Measured using the European gravimetric transfer sampler or equivalent.

ng m-3 - nanogrammes per cubic metre
µg m-3 - microgrammes per cubic metre
mg m-3 - milligrammes per cubic metre

** Represented using µg m-3 as NO2

*** Benzo[a]pyrene is used as a marker for the carcinogenic risk of polycyclic aromatic hydrocarbons in ambient air.

Objectives for arsenic, cadmium, nickel and Benzo[a]pyrene are Target Values.

(V) These standards are adopted for the protection of vegetation and ecosystems. All of the remainder are for the protection of human health.