The protected area or NIPAS area in the municipality is the Bulusan Volcano Natural Park located at barangay Cogon with an area of 1,045.71 hectares. The BVNP consists of montane and lowland forest in a mountain complex covering the municipalities of Irosin, Juban, Casiguran, Barcelona and Bulusan with a total area of 3,673.29 hectares. Biodiversity profile of the BVNP includes threatened bird species of Philippine Duck, Philippine Hawk-eagle, and Flame-breasted Fruit-Dove as well as restricted-range bird like Luzon Bleeding-Heart, Luzon Hornbill and others. Mammals that have been recorded include Philippine Brown Deer, Philippine Warty Pig and the threatened Giant Cloud Rat. Endemic herpetofauna include forest frogs, tree skinks and the continue reading : Environmental Conditions
The existing land uses in the municipality are categorized into: Urban Use Areas (residential, commercial, infrastructure/utilities, institutional, parks/playgrounds and industrial), Agriculture, Forest and Forest Use, Agro-Industrial, Tourism, Other Uses (cemeteries, dumpsite/sanitary landfill, vacant lands) and Water Uses.
The soil type of the municipality is of volcanic origin of alluvial deposit ranging from sandy loam to silt loam. It is classified into six major soil types which are best suited for agricultural purposes. The soil type consisting vast track of rice paddies located within the valley floor are Irosin Silt Loam and Irosin Sandy Loam with an aggregate area of 2,988 hectares or 21% of the total land area of the municipality.
Irosin is a second-class municipality with a total operating income of P 114,831,093.85 in 2015. The two revenue sources are local sources and external sources. Locally generated income comprises tax which is 4.7% of the total income and non-tax revenues which is 5.8%. Revenues from external sources consist of share from Internal Revenue Allotment which is 88.8% of the total income in 2015. The total current operating expenditures in 2015 is P 83,931,685.55 of which 65.3% is expended on General Public Services, 1.7% for Education, Culture and Sports 3and Manpower Development, 10.2% on Health and Nutrition, 4.57% for Housing and Community Development, 6.94% for Social Services and Social Welfare, 10.38% continue reading : FISCAL MANAGEMENT
In built-up areas, the most pressing environmental concern is the increasing volume of solid waste being generated by the growing number of household and commercial establishments. The per capita waste generation is rising as more Irosinians adopt a consumerist lifestyle and prefer disposable or single-use products and non-biodegradable packaging materials. A waste characterization study in 2002 showed that about 86% by weight of solid waste from households is organic materials, approximately 10% is recyclable and only 4% is residual waste. The study showed that 96% of solid waste from households is recoverable resource and only a small fraction is fit for final disposal.