4 Particles

4.1 Pollutant concentration maps
Maps of estimated annual mean background PM₁₀ concentration have been calculated for 1995, 1996, 2000, 2004 and 2005. Details of the methods used to calculate these maps are given in Stedman, Linehan et al (1998).

While maps of current annual mean PM₁₀ concentrations have been previously presented by Stedman (1998), maps of annual means and number of exceedance days, for comparison with the existing PM₁₀ NAQS objective and European Union 'Daughter Directive' 24-hour and annual limit values for both current and future years have been calculated by Stedman, Linehan et al (1998). The daily PM₁₀ receptor modelling methods developed for the Airborne Particles Expert Group report (APEG, 1999) and annual mean mapping methods of Stedman (1998) have been combined to produce daily maps of background PM₁₀ concentrations.

Daily mean maps for the UK were calculated every day for both 1995 and 1996 by combining maps of secondary particles (derived from interpolated daily rural sulphate data), coarse particle maps (derived from an interpolation of the daily estimates of coarse particles at urban sites) and primary particle maps consisting of both long range transported primary particles and local primary particles (derived from black smoke measurements and emissions data). The daily maps were then summed to produce an annual mean map for both 1995 and 1996. Projections to 2000, 2004, and 2005 were undertaken, on the basis of current policies, using both of these years as a starting point, in order to assess the influence of different types of meteorology on future concentrations.

4.2 Health benefits resulting from current policies
The estimated health benefits that are expected to result from the implementation of current national policy measures between 1995/1996 and 2005 are listed in Table 4.1. The first column shows the number of deaths or admissions that has been calculated for the individual years for which maps have been calculated. The second column shows the cumulative reduction in deaths hospital admissions calculated by adding up the marginal benefits between 1996 and 2005. Cumulative benefits were calculated by assuming linear changes in health outcomes between 1995/1996 and 2000 and between 2000 and 2005. The benefits in each year relative to 1995/1996 were then summed to give the total benefit over the period.

Table 4.1 Numbers of deaths and respiratory hospital admissions after predicted reductions in levels of PM₁₀ resulting from business as usual (UK Urban population).

Pollutant	Deaths Brought Forward		Emergency Respiratory Hospital Admissions (additional or brought forward)
PM10	In named year	Total reduction (from 1995 or 1996 baseline)	In named year	Total reduction (from 1995 or 1996 baseline)
Baseline 1995
1995	7060		5820
2000	6570		5415
2004	6250		5150
2005	6170	5120	5090	4225
Baseline 1996
1996	7390		6091
2000	6910		5695
2004	6585		5410
2005	6480	4860	5345	4015
Notes Values have been rounded to the nearest 5.

4.3 Health benefits resulting from additional measures
The marginal health benefits due to reductions is PM₁₀ concentration have also been calculated for the alternative emissions reduction scenarios listed in Table 3.2 and the results are listed in Table 4.2. Once again the cumulative total benefits have been calculated on the assumption that the additional emission reduction measures are introduced gradually over the period between 1996 and 2005.

Table 4.2. The impact of additional emissions reduction measures on deaths and hospital admissions attributable to PM₁₀.

scenario	marginal benefit in named year		cumulative total benefit relative to business as usual
	deaths	admissions	deaths	admissions
hl	28	23	140	115
il	9	8	45	40
Notes Marginal benefits in 2005 and cumulative marginal benefits between 1996 and 2005 compared with 2005 business as usual scenario. Base year is 1996 for all calculations

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